1. Field of the Invention
The present invention relates to an airtight container and a display device in which a wiring substrate having wirings arranged inside grooves formed on a surface of the wiring substrate is used.
2. Description of the Related Art
Examples of a flat panel display include a liquid crystal display (LCD), a plasma display (PDP), an inorganic EL display, an organic EL display (OLED), and a field emission display (FED). Those flat panel displays are provided with a flat-shaped airtight container, and a plurality of wirings are formed inside thereof (internal space). In the LCD, inside the airtight container, a liquid crystal material is disposed, and in PDP, discharge gas is disposed inside the airtight container. In the EL display, predetermined gas such as nitrogen is disposed inside the airtight container, or a pressure inside the airtight container is kept lower than the atmospheric pressure. Besides, in FED, the pressure inside the airtight container is kept lower than the atmospheric pressure (preferably in vacuum). Then, the airtight container is formed, for example, by joining outer peripheries of a pair of substrates using a joint member having a sealing function and a bonding function so that the pair of substrates are held at a given gap. U.S. Pat. No. 5,909,033 discloses FED. The plurality of the wirings (wirings formed on one of substrates) formed inside the airtight container need to be extended from inside the airtight container so as to be connected to a drive circuit formed outside the airtight container.
Japanese Patent Application Laid-open No. H09-277586 discloses a technique for solving the reduced airtightness of joint portions in a case where positions for joining between the pair of substrates are set on the wirings for driving respective pixels.
On the other hands, along with progress of attaining high definition of the display, there occurred such cases in which heights of the wirings and precision of the wirings themselves became problems. To cope with those problems, as disclosed in Japanese Patent Application Laid-open No. 2000-251680, Japanese Patent Application Laid-open No. 2006-066337, and Japanese Patent Application Laid-open No. 2007-335241, a method is proposed that involves forming grooves on the substrate to provide the wirings within those grooves. According to this method, the wirings having a large film thickness may be provided onto the substrate by a printing method with high precision. Further, U.S. Pat. No. 5,909,033 discloses a silicon substrate having a concave portion on which a cathode and a withdrawn electrode around the cathode are located.